By Jeff Labrecque
Updated July 17, 2014 at 08:49 PM EDT

Shannon Guess Richardson, a Texas actress who appeared in The Walking Dead and the Sandra Bullock movie The Blind Side, was sentenced to the maximum of 18 years after she admitted to sending ricin-laced letters to President Barack Obama and then lying about it. In May 2013, she sent tainted letters addressed to Obama, New York mayor Michael Bloomberg, and the leader of a national gun-control group. “What’s in this letter is nothing compared to what ive got in store for you mr president,” the letter warned Obama. “You will have to kill me and my family before you get my guns. Anyone wants to come to my house will get shot in the face.”

Richardson had grown the biological toxin herself, and she went to police and blamed the act on her husband, who was in the process of filing for divorce.

In federal court on July 16, Richardson, 36, tearfully pleaded for mercy, referenced her six children, and claimed that she never intended to hurt anybody because she assumed that security measures were in place to protect those who receive official mail. “I don’t feel like I was in my right mind leading up to that point,” she said, according to the Associated Press. Eighteen years was the maximum sentence, and Richardson was also ordered to pay $367,000 in restitution.